Post-Transplant Radiation Had No Impact on Survival in Patients with Refractory or Relapsed Diffuse Large B-Cell Lymphoma

Abstract

Introduction High-dose chemotherapy followed by autologous hematopoietic cell transplantation (AHCT) offers cure for appropriate patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) sensitive to chemotherapy. Post-AHCT consolidative radiation therapy (RT) has been associated with improved outcomes in R/R DLBCL patients with bulky [based on computed tomography (CT)] disease after AHCT. We and others have demonstrated that patients with a Deauville score 4-5 (high-risk) on pre-AHCT FDG positron emission tomography (PET) have significantly worse outcomes as compared to those with Deauville 1-3 (low risk). We here examined the impact of consolidative post-AHCT RT in R/R-DLBCL patients with high-risk functional imaging based on Deauville score) on pre-transplant FDG PET scan on AHCT outcomes. \xa0Therefore, we retrospectively studied the effect of post-ASCT RT within 6 months after ASCT on survival in patients with R/R-DLBCL with high-risk pre-ASCT PET scans. Methods We retrospectively studied 193 consecutive adult patients with R/R-DLBCL identified from the Cleveland Clinic and University of Minnesota who had available pre-transplant FDG PET scans and adequate clinical follow-up. \xa0PET scans were re-reviewed and scored Deauville 4-5 were considered high risk. Patients that died within 6 months of ASCT (n=20) were excluded from the final survival analyses. Univariate analysis was performed using the Kaplan-Meier method, and the log-rank test was used to compare the subgroups. Results The mean (SD) age of diagnosis was 54 (11) years and 61% patients were male. The mean follow-up for alive patients was 43 (32.6) months. We identified 69 patients with pre-transplant Deauville scores 4 (n=41) or 5 (n=28). Seventeen (25%) received RT at median 58 days post AHCT (IQR 39-79 days). Receiving post-ASCT RT did not impact overall survival in univariable (Figure 1) or multivariable analyses adjusted for age and gender. Conclusion Within the limits of the study design, we did not observe a benefit to RT on overall survival in patients with RR-DLBCL with high-risk pre-AHCT PET scans. Alternative treatment approaches for high risk patients based on pre-transplant PET should be investigated in prospective clinical trials.